NOT SURE WHAT YOU MEAN BY "SMALLER DIAMETER CRANK PULLEY"?? IF YOU PURCHASE ORIGINAL EQUIPMENT PULLEYS THE DIAMETER SHOULD BE CORRECT. I KNOW THERE ARE DIFFERENT DIAMETER WATER PUMP PULLEYS AVAILABLE AND OF COURSE THE SMALLER DIAMETER PULLEY YOU CHOOSE TO RUN ON THE PUMP WILL INCREASE THE SPEED OF THE PUMP AND MAY HAVE AN EFFECT ON THE COOLING ABILITY. I HAD THIS ISSUE ON A SMALL BLOCK THAT WAS IN A STREET ROD I PURCHASED AND COULDN'T FIGURE OUT WHY IT WOULD RUN WARM IN TOWN BUT NOT AT HIGHWAY SPEED. FINALLY DISCOVERED IT HAD A LARGE DIAMETER WATER PUMP PULLEY INSTALLED. CHANGED TO A MUCH SMALLER PULLEY AND PROBLEM SOLVED. SUMMIT, JEGS, AND OTHERS HAVE SEVERAL SIZES AVAILABLE. GOOD LUCK.:gba:
Hey Jim I had a 5" diameter crank pulley on my 454 and the alternator charge light wouldnt go off unless I gave the engine a small rev. I changed the pulley to the correct size 7 or 8" or whatever it is and it fixed the problem. I didnt even leave my shed with the smaller pulley on it.
A forum community dedicated to 1955, 1956, and 1957 Chevy owners and enthusiasts. Come join the discussion about restoration, engine swaps, reviews, performance, modifications, classifieds, troubleshooting, maintenance, and more! Open to all models including Belair, 210, 150, Sedans, and Nomads.